Months of wild partying. And now Britney shears in public

In a bizarre twist in the erratic career of America's former princess of pop, Britney Spears has sparked speculation she may be suffering some kind of breakdown after she shaved off her own hair in a shop window.

Spears turned up at a Los Angeles hairdressing salon late on Friday evening, but when staff apparently refused her request for such a dramatic cut, she picked up the electric clippers herself and, as onlookers gawped through the glass, sliced off her long brown hair.

Afterwards, the bald pop star strode into a nearby tattoo parlour in the LA suburb of Sherman Oaks. There, again as passers-by gathered, the 25-year-old had a pair of pink and red lips tattooed on her wrist and a cross on her hip.

As news of her actions began to spread, websites and cable news channels were buzzing with details - and online video - of Spears' appearance. Tattoo store employee Emily Wynne-Hughes told Usmagazine.com Britney had arrived agitated and, when asked why she had shaved her head, replied: 'I don't want anyone touching me. I'm tired of everybody touching me.' Hughes added: 'She wasn't making sense at all and you could tell she's not in a good place. After she left, we just looked around and said to each other, "We just saw a huge celebrity on the verge of a nervous breakdown".'

Spears has lived almost all her life in the harsh glare of the public eye. From Disney child star to teen pop idol to young mother, she has rarely been out of the spotlight that made her world- famous and her albums bestsellers.

But this weekend the cameras were on a different young woman. Not only her hair is gone. Gone too is the perfectly-toned physique of her videos and the fashionable outfits that inspired a generation of American youngsters. They have been replaced by an image of a pale shaven-headed woman, puffy-faced, and wearing a drab grey sweatshirt.

In a nation still agog at the death of reality TV star Anna Nicole Smith, many now fear Spears could follow her down that doomed road. It is a stunning turnaround for a woman who just a few months ago was still married with two children and plotting her comeback album that was set to relaunch her career.

But now the image of a bald, shaven Spears is the talk of America. The news has been given blanket coverage on papers, cable channels and gossip websites. 'Bald Britney Breakdown!' declared the influential Drudge website.

Los Angeles is long-used to the unusual shenanigans of its celebrity denizens, but few will ever have witnessed scenes as odd as those on Ventura Boulevard when a black SUV pulled up outside a closed hair-dressing salon just before 7pm. As staff were called to reopen the business Spears apparently wept inside her car, then went inside and asked to have her hair cut off. When staff refused to carry out the dramatic request, Spears picked up the electric shears herself. Beginning at the front of her head, she started shaving and her dyed black hair fell to the floor in long strands. At times she paused and looked in the mirror or at photographers gathered outside, then completed the task. She had gone from gorgeous pop idol to grim GI Jane.

But the night was not over. Spears next headed for a nearby tattoo parlour called Body and Soul. By this time fans, gawkers and paparazzi had gathered outside. The throng was so big police were called to control the crowd. In front of a phalanx of cameras Spears proceeded to get a tattoo on her wrist of a pair of lips. Then, trying to hide her lack of hair under a grey, hooded tracksuit top, she fought her way through the crowd, helped by police, and drove off in the direction of her home. 'We could see her in the mirror and her head is completely shaved. It looks terrible,' Spears fan Angelique Uram told a local TV station. The latest and most bizarre - but probably not the last - incident in the destruction of Spears' career and reputation was over.

Spears has struggled to make the transition to adult star, a path littered with far more failures than successes. At the same time, her personal life has collapsed. At 25 she is twice divorced and the mother of two children. Her marriage to her second husband, Keven Federline, broke up late last year.

Since the split Spears has embarked on binge of hardcore partying. With celebrity friends such as socialite Paris Hilton and actress Lindsay Lohan, her drunken exploits have been relentlessly chronicled. Along with Hilton, she made the cover of Newsweek in an issue headlined 'The Girls Gone Wild Effect'. That sentiment seemed especially true after a series of evenings out in which Spears was not wearing underwear, established beyond doubt in dozens of explicit pictures.

Last week one of Spears' most trusted former confidantes, Felicia Culotta, went public with her concerns for her old boss. Culotta spent most of the past 10 years as one of Spears' personal assistants and posted an email on a fan website warning that Spears was in the middle of a huge personal crisis. She also admitted she was powerless to help. 'I cannot save her from herself nor can I commit her to any type of treatment programme against her wishes,' Culotta wrote.